Part:BBa_K3176020
Specific aptamer for E. faecium
Aptamers are short single-stranded DNA or RNA oligonucleotides that can be selected to a wide variety of targets. They are similar to antibodies through their affinity and specificity and show a high potential as diagnostic and therapeutic tools, with many advantages when compared with antibodies. BBa_K3176020 is a DNA aptamer selected against E. faecium strain specifically from a random DNA library, using the Whole-Cell SELEX process. Because of its specificity and its affinity, it can be used to detect living E. faecium cells in any clinical samples when coupled to a fluorophore.
Usage and Biology
We tested this aptamer and its ability to detect E. faecium strains by measuring a change in electric potential across the nanotubes. Using our arduino as a voltmeter, we have recorded the response profile of our electrodes following the addition of bacteria at different time points. Electrodes coated with E. faecium aptamers should be only specific to this strain. Each graph represents the potential in mV according to the time in seconds.
As a negative control, PBS has been added on the surface of the E. faecium specific electrode . Two peaks are observed perfectly corresponding to the moment when the drop is added. This environment disturbance may induce a temporary change in potential, before quickly returning to the basic potential.
We then detected a signal in the presence of the targeted bacteria E. faecium. A high change in potential with a staircase profile is observed. Bacteria are thus able to bind to the aptamers, inducing a change in their conformation.
When a solution of E. coli is added, it does not induce any staircase potential jumps as observed for E. faecium. Indeed the profile of the graph is similar to the PBS control when the drop is added, before quickly returning to the basic potential. This observation proves that our aptamers designed for E. faecium are specific to this strain.
We then tested the detection of E. faecium in a synthetic urine solution instead of PBS. Bacteria are also able to bind to the aptamers even if we change the solution in which they are suspended.
Sequence and Features
- 10COMPATIBLE WITH RFC[10]
- 12COMPATIBLE WITH RFC[12]
- 21COMPATIBLE WITH RFC[21]
- 23COMPATIBLE WITH RFC[23]
- 25COMPATIBLE WITH RFC[25]
- 1000COMPATIBLE WITH RFC[1000]
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